As the result was identical, I decided to look for more info in the log file of the new database. What I find was this:

*********************************************************************
Database Characterset is US7ASCII
Threshold validation cannot be done before catproc is loaded.
Threshold validation cannot be done before catproc is loaded.
*********************************************************************
alter database character set INTERNAL_CONVERT WE8MSWIN1252
Updating character set in controlfile to WE8MSWIN1252
Synchronizing connection with database character set information
Refreshing type attributes with new character set information
Completed: alter database character set INTERNAL_CONVERT WE8MSWIN1252
*********************************************************************
alter database character set US7ASCII
ORA-12712 signalled during: alter database character set US7ASCII...
alter database character set US7ASCII
ORA-12712 signalled during: alter database character set US7ASCII...
Errors in file e:\oracle\product\10.2.0\admin\orcl\udump\orcl_ora_3132.trc:

As the result was identical, I decided to look for more info in the log file of the new database. What I find was this:

*********************************************************************
Database Characterset is US7ASCII
Threshold validation cannot be done before catproc is loaded.
Threshold validation cannot be done before catproc is loaded.
*********************************************************************
alter database character set INTERNAL_CONVERT WE8MSWIN1252
Updating character set in controlfile to WE8MSWIN1252
Synchronizing connection with database character set information
Refreshing type attributes with new character set information
Completed: alter database character set INTERNAL_CONVERT WE8MSWIN1252
*********************************************************************

This is an unsupported method to change the characterset of a database - it has caused the corruption of your database beyond repair. Hopefully you have a backup you can recover from. Whoever did this did not know what they were doing.

alter database character set US7ASCII
ORA-12712 signalled during: alter database character set US7ASCII...
alter database character set US7ASCII
ORA-12712 signalled during: alter database character set US7ASCII...
Errors in file e:\oracle\product\10.2.0\admin\orcl\udump\orcl_ora_3132.trc:

Regards

The correct way to change the characterset of a database is documented - http://docs.oracle.com/cd/B19306_01/server.102/b14225/ch11charsetmig.htm#sthref1476